Sex-Influenced
Trait
and
Epistatic Interaction
Only heterozygous polled
cattle ever grow scurs (see red section in Table below), which is the epistatic
interaction. Two scurred alleles
are required in females and only one in males, which is typical of a
sex-influenced trait.
|
Genotype |
Cows
|
Bulls |
|
PP Sc/Sc |
smooth polled |
smooth polled |
|
PP Sc/sc |
smooth polled |
smooth polled |
|
PP sc/sc |
smooth polled |
smooth polled |
|
Pp Sc/Sc |
scurs |
scurs |
|
Pp Sc/sc |
smooth polled |
scurs |
|
Pp sc/sc |
smooth polled |
smooth polled |
|
pp Sc/Sc |
horned |
horned |
|
pp Sc/sc |
horned |
horned |
|
pp sc/sc |
horned |
horned |
P = polled allele
P = horned allele
Sc = scurred allele
sc = allele for no scurs
Sheila Schmutz, PhD. Jan. 31, 2007